Security

Login to https://appleid.apple.com/

All the devices that are REALLY connected to your AppleID will be listed.

Simply delete any devices you don’t recognize.

And if there ARE some unrecognized devices … change you AppleID password as well.

Lasyly, while you’re there, seriously consider activating 2-Factor authentication if you’ve not done so already.

Two-factor authentication for Apple ID - Apple Support

Check your device list to see if there is a device signed in that you don't recognize. You can remove the device using the steps in the article below. As a precaution, change your password.

Apple ID device list -Check to see where you‘re signed in.   * 

 Apple ID Password Change.   -  

ASC YouTube for How to reset your Apple ID password

 What to do after you change your Apple ID or password - Apple Support  -   I suggest doing this before you change your Apple ID or password.